topic Re: GDL - get value before parameter change in GDL

GDL - get value before parameter change

Darwuhr — Sat, 24 Sep 2022 21:17:43 GMT

If I change the vakue of a paramter, either via objects settings dialog or editable hotspot, can I get the value of the parameter before the change? Example I change the parameter x1 via editable hotspot. I want to store the value of x1 before the change so I can do some extra needed calculations. So I will have the x1 param with the new value and another param that will have the value of x1 before the change.

Re: GDL - get value before parameter change

runxel — Sat, 24 Sep 2022 23:45:23 GMT

Use a shadow parameter for that.

Re: GDL - get value before parameter change

Darwuhr — Sun, 25 Sep 2022 06:26:23 GMT

Could you explain what a shadow parameter is and how to apply one?

Re: GDL - get value before parameter change

runxel — Sun, 25 Sep 2022 10:02:16 GMT

It's called like that because you're shadowing one parameter to another, invisible one (for the user).

Just make two parameters for every parameter setting you'll need. One is hidden for the user ('X' it), the other one is the main input.

Pseudocode:

! ::Master or Param script:: if GLOB_MODPAR_NAME = "myparam" then ! do your calculations ... ! finally mirror the current value to the shadow parameter: myshadowparam = myparam endif ! … and set the parameter value parameters myshadowparam = myshadowparam